This invention relates to the splitting of alkylenebisphenols. In another aspect, this invention relates to a catalytic process for the conversion of alkylenebisphenols to phenol and alkyl- and/or alkenyl-substituted phenols. In accordance with another aspect, alkylenebisphenols are cleaved in the presence of hydrogen and a catalyst comprising nickel oxide and manganese oxide and a metal oxide support. In accordance with another aspect, the effectiveness of the catalyst is improved with respect to conversion and selectivity by calcination under selected conditions.
The hydrogen atoms attached to the carbon atoms ortho or para to the carbon atom containing a hydroxyl group in phenol are highly reactive and can readily lead to substitution in these positions. Because of this high degree of reactivity, direct substitution generally yields a mixture of ortho- and para-substituted phenols which are often difficult to separate. An alternate method of preparing a phenol where substitution is in only one position is to decompose or degrade an alkylenebisphenol. This usually will give a phenol and an alkylphenol. Alkylenebisphenols such as 2,2-di(p-hydroxyphenyl) propane, referred herein as bisphenol A, have been reported as being cleaved with acids or bases to give phenol and p-isopropyl or p-isopropenylphenol. These methods are reported in U.S. Pat. Nos. 3,466,337; 3,075,015; and 2,497,503. All of these methods suffer from the disadvantage that added neutralization and/or separation steps are necessary to remove the active cleavage ingredient. U.S. Pat. No. 1,788,847 discloses the use of a carbonate or hydroxide of a metal which catalyses hydrogenations as a useful catalyst in the cleavage of bisphenol A. This process, however, requires the use of steam or an inert gas along with hydrogen to conduct the cleavage and the metal to be used is not specifically defined. Likewise, the art in J.C.S., 1948, 164-167 describes the catalytic cleavage of bisphenol A in the presence of hydrogen and a copper chromite catalyst. The yield of p-isopropylphenol is about 88 mole percent. The reaction is a batch reaction conducted over a 5 hour period at 180 atms. (2520 psig). Therefore, it is desirous to produce p-isopropylphenol or other mono-substituted phenols in high yields in a continuous process at modest or low temperatures and pressures.
An object of this invention is to provide an improved process for the cleavage of alkylenebisphenols.
Another object of this invention is to provide an effective catalyst for the cleavage of bisphenols.
Another object of this invention is to provide a process exhibiting increased conversion and increased selectivity to desired products in the conversion of alkylenebisphenols.
Other aspects, objects, and the several advantages of this invention will become apparent to one skilled in the art upon reading the specification and appended claims.